The research of OLED devices has been developed comprehensively and thoroughly since the light emitting phenomena of organic molecules was discovered by Professor Qingyun Deng. OLED devices have been widely applied in the field of display technology because these devices have advantages of high efficiency, low power consumption, wide color gamut and the like. Based on the light emitting material, OLED can be substantially classified into two kinds, one comprising fluorescent material and the other comprising phosphorescent material. More attention has been paid to the phosphorescent material due to its high internal quantum efficiency.
However, the phosphorescent material tends to experience self-quenching for the triplet state of molecular excitation. Especially in the case of high current density, the phosphorescence material is more easily to suffer from a loss as a result of the self-quenching, thereby reducing the lightness of a phosphorescent OLED.
In addition, although the research and development techniques of the phosphorescent OLED devices has been relatively mature at a laboratory level, but there still exists some problems in practical, for example, the life of a phosphorescent OLED device is susceptible to the environment. It is well known that the phosphorescent OLED device is extremely susceptible to moisture and oxygen, especially the moisture. If the moisture permeates into the device, a dark spot in the light-emitting region, which will expand over time, is easily caused, thereby affecting the display quality and the life of the device. Currently, the occurrence and expanding of the black spots were prevented mainly by encapsulating the phosphorescent OLED devices. Encapsulation technology mainly includes cover plate encapsulation technology such as metal cover plate encapsulation technology and glass cover plate encapsulation technology and the like, and film encapsulation technology represented by Barix film encapsulation layer (developed by Vitex Systems Company). However, for these prior art, there are disadvantages such as surface irregularities (such as in the case of metal cover plate encapsulation) and occurrence of microcracks (such as in the case of glass cover plate encapsulation), as well as high-costs and the complicated production process (such as in the case of Barix thin film encapsulation).